INTRODUCTION: Influenza is a common febrile illness with a significant impact on the pediatric population. Few data regarding influenza in young children have come from tropical resource-limited countries.
OBJECTIVE: We aimed to study epidemiological data, clinical manifestations, influenza rapid tests, and oseltamivir treatment in children with influenza.
METHODS: We conducted influenza surveillance at Queen Sirikit National Institute of Child Health, a tertiary care children's hospital in Bangkok, Thailand. From July 5, 2004, to July 3, 2005, 2 groups of patients aged 0 to 5 years were enrolled: (1) patients diagnosed with lower respiratory tract infections (ie, viral croup, bronchitis, bronchiolitis, and pneumonia) and (2) patients diagnosed with influenza-like illness on the basis of World Health Organization criteria. Subjects must have had symptoms for <5 days. We collected nasal swabs to perform influenza A antigen tests by rapid-test kit and nasopharyngeal swab to perform viral cultures. Clinical signs and symptoms were recorded. Oseltamivir (Tamiflu) was given to the patients with positive rapid-test results, and parents agreed to receive an antiviral agent. Other treatment was provided by attending physicians as the routine standard of care.
RESULTS: We enrolled 495 patients, 49 (9.9%) of which had influenza virus. The virus was isolated year-round with 2 peaks. Fever and myalgia were symptoms with a statistically significant difference between patients with and without influenza infection. The rapid test for influenza A showed 51% sensitivity and 98% specificity compared with viral culture. Eighteen (37%) of 49 patients received oseltamivir treatment. The oseltamivir-treated patients had, on average, 1.12, 0.41, and 0.55 days' shorter oxygen duration, hospital stay, and time to improvement, respectively, but there was no statistically significant difference.
CONCLUSIONS: Influenza in young children in Thailand can be found in 10% of patients with lower respiratory tract and influenza-like illness. Two peaks occurred during July to October and January to April. Rapid-test kits have moderate sensitivity but high specificity. Benefit from oseltamivir treatment was observed but not statistically significant.